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Gut bacterial profile in patients newly diagnosed with treatment-naïve Crohn's disease

Authors Ricanek P, Lothe, Frye S, Rydning A, Vatn M, Tønjum T

Received 14 May 2012

Accepted for publication 2 July 2012

Published 24 September 2012 Volume 2012:5 Pages 173—186


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Petr Ricanek,1,2 Sheba M Lothe,1 Stephan A Frye,1 Andreas Rydning,2 Morten H Vatn,3,4 Tone Tønjum1,5

1Centre for Molecular Biology and Neuroscience and Department of Microbiology, Oslo University Hospital, Rikshospitalet, Oslo, 2Department of Gastroenterology, Akershus University Hospital, Lørenskog and Faculty Division Akershus University Hospital, University of Oslo, Lørenskog, 3EpiGen Institute, Faculty Division Akershus University Hospital, University of Oslo, Lørenskog, 4Department of Medicine, Oslo University Hospital, Rikshospitalet, Oslo, 5Centre for Molecular Biology and Neuroscience and Department of Microbiology, University of Oslo, Oslo, Norway

Objectives: The aim of this study was to define the composition of the gut bacterial flora in Norwegian patients with early stage Crohn's disease (CD).
Methods: By using a nonselective metagenomics approach, the general bacterial composition in mucosal biopsies from the ileum and the colon of five subjects, four patients with different phenotypes of CD, and one noninflammatory bowel disease control, was characterized. After partial 16S ribosomal RNA (rRNA) gene sequencing, BLAST homology searches for species identification and phylogenetic analysis were performed.
Results: An overall biodiversity of 106 different bacterial operational taxonomic units (OTUs) was detected in the cloned libraries. Nearly all OTUs belonged to the phylae Bacteroidetes (42% in CD, 71% in the control) or Firmicutes (42% in CD, 28% in the control), except for some OTUs that belonged to the phylum Proteobacteria (15% in CD, 0% in the control) and a few OTUs that could not be assigned to a phylum (2% in CD, 1% in the control).
Conclusion: Based on the high incidence of inflammatory bowel disease (IBD) in Norway, this pilot study represents a relevant determination of the gut microbiota in Norwegian patients compared to previous findings in other countries. The bacterial profile of Norwegian CD patients was found to be similar to that of CD patients in other countries. The findings do not support a particular bacterial composition as a predominant causative factor for the high incidence of IBD that exists in some countries.

Keywords: Crohn's disease, gut microbiota composition, inflammatory bowel disease, IBD, metagenomics, 16S rRNA gene sequences

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